ProPublica reported in July that in the last five years, police responded to at least 125 calls alleging sex offenses in 70 of 100 immigrant youth shelters run by the U.S. Health and Human Services department’s Office of Refugee Resettlement. And some experts said that that number is likely an inaccurate representation of a bigger problem because children are often reluctant or too frightened to report abuse.

Magarin did not name the shelters where the alleged abuse of the Salvadoran children occurred, nor did she offer any other details. But a 32-year-old worker in a privately run shelter in Phoenix has been charged with sexual assault of a 14-year-old migrant in July. It could not immediately be determined what country the child was from.

Shelter operator Southwest Key Programs told the newspaper the worker was fired after the incidents.

Another former employee of Southwest Key went on trial Tuesday on charges of sexual abuse that allegedly occurred before the Trump administration’s family separation policy went into effect. The employee, who is HIV-positive, has been charged with performing sex acts on two teenage boys and inappropriately touching six others in 2016 and 2017 at a shelter in Mesa, Arizona, according to NPR station KJZZ.

Southwest Key is a Texas-based non-profit that houses more than 1,500 migrant children in Arizona, California and Texas under a 2018 federal contract worth $458 million.

Critics complain that youngsters are particularly vulnerable in the sudden imposition of family separation. They’re brought without parents or guardians into hastily arranged shelters with little time for administrators to adequately screen workers for jobs that tend to attract sexual predators.

“If you’re a predator” such shelters are a ‘gold mine,’” Lisa Fortuna, director of child and adolescent psychiatry at Boston Medical Center, told ProPublica. “You have full access and then you have kids that have already had this history of being victimized.”

The inspector general of the Office of Refugee Resettlement has announced plans to visit shelters across the country to “identify vulnerabilities.”

Margarin said 191 Salvadoran children were separated from their parents at the border in recent months, and 18 remain in shelters. She said the El Salvador government is pressing the U.S. for reunification as quickly as possible because shelters are where the children are the “most vulnerable.”